Technologies and Costs for Removal of Arsenic From Drinking Water

For design flows greater than 1 mgd, the building cost varied based on flow from $100 to $90per square foot.Design Assumptions: Operation and Maintenance (O&M) CostsThere are major components to the operation and maintenance (O&M) costs are regenerationfrequency, regeneration dose, and incremental labor. See Appendix E for more detail.1. The critical variable in calculating the regeneration frequency is the run length - the numberof bed volumes until the effluent concentration exceeds a specific concentration. The runlength when sulfate is at or below 20 mg/L is 1500 bed volumes (BV). The run length whensulfate is between 20 and 50 mg/L sulfate is 700 BV.2. The regeneration dose is also a critical element for the O&M costs. The salt dose forregeneration was 10.2 lb/ft 3 .3. The second major component in the O&M costs is incremental labor cost. Incremental laboris the labor associated with the additional maintenance that comes with a new process.Adjustment in staffing or shifting of activities are not included in the incremental labor. Theincremental labor for the anion exchange is one hour per week plus three hours perregeneration.4. The labor rate for small systems was $28/hour. The loaded labor rate for large systems was$52/hour.5. O&M Costs were calculated using the data on regeneration dose, regeneration frequency,labor hours per week and adjusted labor rates using the equation in the Very Small SystemsDocument.The capital and O&M cost curves for anion exchange are shown in figures 3-16 through 3-19.3-50